That's the worst part. They don't do this in the field. They do it at home to save themselves the trouble of cleaning a weapon properly, because unscented shaving cream supposedly will dry a weapon out and pull all the carbon out of the metal. I have no idea if this is true or not, but it is a very popular rumor.

What can tell you is that when people do it and then don't immediately clean it all out, it fucks the weapon up pretty badly. We just had to turn in a 240 that was green on the inside due to some shaving cream treatment that a couple privates tried to do to it. Which is hilarious, since they probably walked right past the solvent tank on the way out the door to buy the shaving cream.

The two worst things I saw related to weapons cleaning during my time in the army were these:

When I was armorer for my MI detachment we shared an arms room with a supply unit down the road. Someone turned in a rifle that had been cleaned with what must have been a drill attached to the cleaning rods and a bore brush. The rifling was torn to crap.

The second is my HUMINT team leader when I was in Iraq. She knew I had been an armorer in my old unit so when her pistol stopped working she brought it to me. Well... half an hour later, I've finally got it apart and I'm realizing that the only thing wrong with this particular M9 is it hasn't been maintained in I have no idea how long. (Had to be less than 9 months, since that's about how long we'd been in country at that time.) By the time I was done restoring it to working order I had spent 3 hours and was seeing red, since this was the only weapon she was assigned and we were outside the gates every day. I reamed her out in front of the company commander and somehow managed to avoid an article 15 from it. Whee-hoo.

Oh, and back to the tiny pistols and giant battle rifles thing, I'm guessing it has to do with chamber pressures. As the technology has progressed we've seen pistols getting smaller with large rounds and IIRC the .308 is essentially a higher-pressure replacement for 30-06.

As you can see 5.56 Nato does #$%-all against it. While the .458 Socom penetrates it after a couple of shots.

You did notice that there was sand pouring out of those cinder blocks, right? It seems to me that once they shot up the wall and the sand was very close to done pouring out pretty much anything is going to shatter those blocks. They become a lot more like the blocks in the previous video with no material inside to diffuse the force of the blow.

EDIT: Don't think I'm defending 5.56mm, just noting a discrepancy between the two videos.

.458 SOCOM is not practical. 6.5 grendel is not practical, considering what it would cost to convert every single weapon over to it, alter production quotas, and then waste billions giving out fat no bid contracts semi-related to the issue. The military will move away from the M16/M4 just as soon as it figures out how to miniaturize railguns, lightsabers, or lasers.

.458 SOCOM is not practical. 6.5 grendel is not practical, considering what it would cost to convert every single weapon over to it, alter production quotas, and then waste billions giving out fat no bid contracts semi-related to the issue. The military will move away from the M16/M4 just as soon as it figures out how to miniaturize railguns, lightsabers, or lasers.